"I will never kick a rock"

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Rocks with SoleThe Woodstock TimesA long time agoUpdated by Robert and Johanna Titus

The Austin Glen Formation is not all that impressive a rock to look at. It’s made up of alternating strata of gray sandstone and black shale. But in many ways, it is one of the most awe-inspiring rock units in the area. It makes up much of the bedrock on the east side of the Hudson River. Travel across the Kingston-Rhinebeck Bridge and it makes up the first outcroppings of rock you will see. These are the low cliffs on either side of Rt. 199. We made the trip recently and took a good look at these outcrops. About 30 paces east of the beginning of the west-bound lane’s exposure we found a remarkable sedimentary structure: One overhanging stratum of rock displayed a crenulated surface. We recognized the form as a type of “sole mark” and it conjured up quite an image from the past.
The sands and muds of the Austin Glen were deposited in some of the deepest waters that make up ocean basins. There is a wonderful word, “abyss,” used to describe great depths in the sea. The abyssal plain is a great vast flat sea floor, about two miles down. But we are talking about something even deeper. We are speaking of a sea floor zone called the hadal zone, that’s a great deep trench at the bottom of the sea and it can be several tens of thousands of feet deep. Today’s Marianas Trench is the best such example we can go see. It is 36,000 feet deep, an incredible depth. We don’t think that the Austin Glen was quite that deep, but who knows for sure.
Not only is a marine trench of this sort deep, but it is also very steep-sloped and that gets us to today’s story. You see, the shales of the Austin Glen formed originally as black muds. It’s typical for such great depths to accumulate muds; the fine clay particles settle to the deep-sea floor and make up the muds. But the sands are different; sands are usually shallow water deposits. Obviously, the sandstones of the Austin Glen weren’t shallow water deposits so how did they get there?
The answer it that the sands were once part of something called turbidity currents. These are very fast-moving currents of dirty (turbid) water that rushed downslope at speeds of up to 50 mph. More likely than not, an ancient earthquake struck and displaced a large amount of shallow water, sandy sediment. Billowing masses were thrown up into suspension by the quake and then they began to flow downhill under the influence of gravity, soon accelerating to their rapid pace. A turbidity current is one of those very powerful forces of nature. Fortunately, there are few animals that stand in the way and few deaths result. There is some destruction, but only in the form of rapid erosion of sediments crossed by the current.

At the bottom of the slope the turbidity currents slow down but, still moving rapidly, they spread out across the soft muds and deposits their sandy sediments. The sudden deposition of sandy sediment upon soft muds has an interesting effect. As the sand spreads out across the sea floor, it presses into the soft muds. The results are the crenulated surfaces we described earlier. They are called sole marks. There are a number of different types of sole marks and, technically, these ones are called “squamiform load casts.” Let’s not get too concerned with the exact terminology and instead try to appreciate the aesthetics of these structures.

They are rather remarkable in the details of their sculpturing and we have trouble finding just the right adjectives for them. Take a look at our illustration and you will get a good impression of them. These soles are common throughout the Austin Glen Formation and, once you have an eye for them, you may be able to find others. We origins: underwater avalanches, triggered by great earthquakes; it’s quite a scenario and very typical of what we find when we know what to look for in the rocks.
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Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

Tub thumping at Kaaterskill Falls
On the Rocks
The Woodstock Times
April 14, 2015
Robert and Johanna Titus

Have you been to the new trails at Kaaterskill Falls? We lobbied for this sort of thing for many years. The DEC seems to have been influenced, in part, by this column in the Woodstock Times.

The year 2014 was a difficult one at Kaaterskill Falls. That summer two people fell to their deaths. It’s a dangerous place; you only have to be careless for a second or two and then the worst can happen. Naturally, everyone involved is quite concerned about the upcoming summer season. We wish these things did not happen, but they do. And there is so little that you can do to mitigate this sort of thing. They have put some new fences up, but they are unlikely to deter people from going into dangerous areas. Some better communications are now available for first responders, and we understand that the site is better prepared to get helicopters in and out of it.
Still, it just takes a second or two for the worst to happen,
But we are concerned about other problems at Kaaterskill Falls, and those are problems that may actually have solutions. Our first concern is the ongoing erosion of the slopes just to the right (east) of the falls. It has been about two centuries now, that people have been coming here in ever increasing numbers. It used to be that the marked Yellow Trail ascended the slope to the right of the falls and people climbed up to the top of the falls that way.
But the ground is soft there and, especially when it is wet, the results of climbing are to mobilize the earth. There is no hope for vegetation to take hold here; plants are quickly trodden into the ground. When it rains, the bare earth is likely to slide downhill, just a bit: just a bit today, and just a bit tomorrow, and just a bit next week. You get the picture. The slopes have been eroding for all those two centuries.
Years ago, the Yellow Trail, above the base of the falls, came to be closed. That probably has helped a little bit, but just a little bit. People still climb up those slopes: we confess; we are among them. It’s not likely that this will stop. Late, last summer, those new fences were put in, but it is hardly likely that these will even slow people down. We posted a photo of one new fence on our Facebook page and the responses were uniformly sarcastic.
So, if this is not working, then what should be done? Our solution, and we have been arguing this for 20 years, is that a staircase should be built. That’s certainly not an unprecedented idea. When William Henry Bartlett sketched at Kaaterskill Falls during the 1830’s, his picture showed a staircase from the bottom to the top of the falls.

Detail from Bartlett print of Kaaterskill Falls. See staircase to right.

But during the last century, this property came to be owned by New York State, and thus part of the Catskill Park. If we understand it properly, park land should not have artificial constructions on it. This land is supposed to be pristine and natural. A staircase would be unnatural, a violation of what is intended. The irony is, of course, that, without a staircase, people do far more harm.
So those “pristine” slopes have been slowly and steadily deteriorating for centuries now: with more centuries to come? We hope not. If we are looking for precedents, we do not just have to visit the 1830’s; we can look at a good example today. Have you ever been to Mine Kill Falls? Take Rte. 30 north from Grand Gorge and watch for signs that announce the presence of the falls. There is an ample parking lot and, just below that, you can begin descending a nice dirt trail into the Mine Kill Gorge. The trail will take you all the way to the bottom of the falls. Your boots will do little damage here; the slope is so gentle that you will not trigger any significant erosion.

But, there is another trail. Its left fork takes you to a staircase and that staircase takes you to a fine view of the upper Mine Kill Falls. Then there is a right branch; its staircase takes you to a view of the lower falls and the canyon below it. It is a most remarkably picturesque location. And we don’t think you will find that the scenery is harmed in any way by the staircases. You will not likely find this to be some sort of environmental abomination.
The steps get people to the upper falls safely and easily. And there is absolutely no erosion going on below the stairs, nor will there ever be any. It is a nice, environmentally sound, solution to a serious problem. Visit Mine Kill and see for yourself. Then imagine some equivalent installations at Kaaterskill Falls.
But there is more, there is another problem that we wish to help solve. The two of us belong to the Mountain Cloves Scenic Byways Committee. We are hoping to promote greater eco-tourism in our picturesque eastern Catskills. We need a trail system that smoothly transports hikers from below Kaaterskill Falls, past the falls, and on to the Blue Trail that leads to the north rim of Kaaterskill Clove. In short, we want a well-planned trail system that promotes green tourism.
We don’t have that now. Today, you can take the Yellow Trail to the base of Kaaterskill Falls and then you are supposed to turn around and go back. Who on earth would want to do that? Our proposed staircase, we hope, would lead on, above the falls, to join the greater trail system. It would be a great lure for tourism in our area. We need it.
This is Greene County; our tourist industry has long been deeply depressed. Greene County is a landscape of lost hotels, empty motels, and long forgotten boarding houses. This, the onetime home of the Catskill Mountain House Hotel, now has very few overnight rooms and still fewer people looking for them. We need help and, just maybe, a more thoughtful trail system would be a step in the right direction. That all hinges on a staircase being installed at Kaaterskill Falls.
We don’t do a lot of tub thumping at On the Rocks, but we think this is worth the effort.
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Contact the authors at randjtitus@prodigy.net. Join their Facebook page “The Catskill Geologist”

Living on AtlantisStories in StoneThe Columbia County IndependentDecember 2005Updated by Robert and Johanna Titus – July 12, 2018

It was 2,300 years ago that Plato wrote of a great island, “larger than Libya and Asia taken together.” His island was the fabled Atlantis and it lay out in middle of the Atlantic Ocean, beyond the Straits of Gibraltar. The story went on: fully 9,000 years before Plato’s time, Atlantis was a great city state which controlled an empire extending as far east as Egypt and Italy. After fighting and losing a war with the Athenians, Atlantis was consumed by a day and a half of earthquakes and floods. The whole land mass sank into the ocean and it has been lost ever since.
It’s a wonderful story and just the type that that we scientists love to debunk. But the word debunk implies ridicule, and when you ridicule a popular myth, you run the risk of appearing arrogant. Now, believe us, arrogance is not exactly unheard of in science, so let’s take a careful look at the story of Atlantis. We will find, as is so often the case, the true story is a lot better than the myth.
You can start by traveling to west of the Hudson River and gazing back eastward from any prominent high point, preferably the top of the Catskill Front. A lot of geologists have done this. They are looking at Columbia County and the profile of the Taconics, but nearly all have pondered the same question: Where did all this rock come from? Beneath them, the Catskill Front is made of 17,000 feet of sandstone shale and limestone. That’s only a small part of what is sometimes called the “Appalachian sequence.” The whole sequence consists of sedimentary rocks about 40,000 thousand feet or so thick. It wasn’t always rock, it was once all sediment. Sediment has to come from somewhere and 40,000 feet of it has to come from somewhere—and somewhere big, so you can appreciate the geological curiosity.
In the 1840’s James Hall, the great Albany geologist, got very interested in finding where all those sediments had come from. He traced them all across North America and soon convinced himself that the thick Appalachian deposits always thinned to the west. It must be, he thought, that if the sediments thinned to the west, then they must have come from a source in the east. Now James Hall had no interests in the myth of Atlantis, but other geologists wondered about that sourceland. Was this the real Atlantis?
In the late 19th century, Charles Callaway calculated the total volume of sediment that made up the Appalachian sequence. From this he judged that there must have once been a sourceland out in the North Atlantic. He estimated it to be about the size of Australia. Callaway thought that the weathering and erosion of this sourceland provided the sediments of the Appalachian sequence and also similar rocks in Europe. Callaway thought that he had come up with the scientific discovery of an ancient lost continent–a real one! He called it “Old Atlantis.” Old indeed, Callaway’s continent was about 400 million years older than Plato’s one.

Callaway’s cross section of “old Atlantis” and its sedimentary rocks.

Callaway’s idea remained popular into the 20th century, but as science progressed, it didn’t hold up all that well. Oceanographers were learning more and more about the floor of the North Atlantic. Surely, they reckoned, if there had once been and Atlantis out there, then some remnant would still remain, but none was ever found.
The solution to the source land problem came in the late 1960’s and it was a terrific story, much greater than the old myth. Continents and oceans, it turned out, were not eternal. Once there had been no Atlantic Ocean at all, neither was there a North America or Europe. Instead there were great land masses, ancestral to the ones that we are familiar with today. Back then, an ancestral Europe was drifting westward and actively colliding with an earlier form of North America. As the two crushed together a great mountain range was thrust up all along the collision zone. Such things do happen and can even be seen today. India is colliding with Asia and the Himalayas are the product of that collision. Our Taconics and Berkshires are part of the 400 million year old ancestral Appalachian system. At their peak they were called the Acadian Mountains and they, not Atlantis, provided the sediments we see today in places like the Catskills.
So the Atlantis of Plato’s myth never did exist. But when we debunk his story, it’s not arrogance, but confidence that science can provide a better story which motivates us. Our story tells of moving and colliding continents. The story speaks of once towering mountain ranges which are no more. It’s a great yarn and one of the most important scientific discoveries of the last century. And to us, the best is that the story comes from the stones.
So find the time someday to take a hike up to the top of the Catskill Front and gaze east. Find the Taconics and Berkshires on the distant horizon. That’s Columbia County below them; it’s all “Atlantis!” Adds something to the view, doesn’t it?

One of the great tourist attractions of our area is Olana, the one-time home of painter Frederic Church. We stood on the bank in front of the south-facing porch of the old mansion and gazed at its fine view of the Hudson Valley and Catskill Mountain. This is one of the great vantage points from which to see the Catskills. There are days when the atmospheric conditions are just right and the mountains seem to reach out to you. It’s not just a view; this is also a genuine work of art. Frederic Church intended the porch should have this vista; it is, among many others, one of his “planned views.” For thirty year he was able to enjoy the scene and we envy him that.

But as geologists, we are privileged to see some other views at Olana. On that wonderful site our minds drifted back into deep time. We were at the bottom of the oceanic abyss that was once here. The waters were tens of thousands of feet deep, cold and black but, more than anything else, they were still and silent. This was a dead seafloor. Nothing crawled across the sea floor and nothing swam in the waters. We scooped up some of the mud; it was soft and sticky. It was foul with the remains of dead microbes that constantly rained in from above.

With time the submarine avalanches came. Geologists call them turbidity currents. The stillness was abruptly interrupted as the sea floor was jolted by seismic shocks. An earthquake had struck. Shortly thereafter great masses of sediment began tumbling down the steep slopes. For long minutes there was the rush of dirty water into the abyss. The torrent boiled as murky clouds billowed upwards all around us. Then the current slowed and gradually the water cleared. The Olana sea floor returned to its silent dead, stillness.

Our mind’s eyes rose through tens of thousand of feet of quiet water until they reached the surface of the sea. We gazed eastward and saw dense black clouds rising above the horizon. The blackness drifted our way and soon it rained volcanic dust into the water all around. Then we looked back eastward again, and now a rising landmass had replaced the black clouds on the horizon. The stark profile of volcanic mountains defined this new horizon

The passage of time accelerated. As we watched, this landmass grew taller and its shores swelled out toward us. We were soon lifted out of the sea by the rising gray crust. Occasional, the earth beneath us shook with powerful quakes as the land rose higher and higher. Eventually, we found our imaginary selves high atop a still rising Taconic Mountain range. To the north and south, volcanoes continued erupting in violent spasms. Below, to the west, what was left of that deep sea retreated away from the rising mountains.

There should have been a great deal of green in this image but there was none. This was a fine range of mountains, but it was a dead landscape that had replaced a dead seafloor. We were in the Late Ordovician time period, about 450 million years ago, and life, especially plants, had not yet managed to colonize the lands. All around us was a bleak, blue-gray landscape. There were not even proper soils, just a litter of gray gravel lying upon bare rocks. Only the dry channels of gullies and ravines broke the monotony of the desolation.

We realized that we had come to the very spot where, 450 million year later Frederic Church would stand. But we were not seeing what he would see. No, below us and stretching off to the west, a large river delta had formed adjacent to the rising Taconic Mountains. A complex of murky streams crossed the dark gray of that delta. Farther away we could see the retreating waters of the sea. It was bleak and lifeless vista, but there was grandeur in this, Olana’s great unplanned. view.

Once you begin to notice it, Cairo Round Top is a mountain you can see from all sorts of places within the Hudson Valley. It can be seen from the north and south and from above and below. It’s aptly named and rather picturesque for its smooth rounded profile, but the question that emerges is how did it get there.

Round Top rises above Cairo

Any geologist, working in this region, would immediately guess that glaciers had something to do with it. And that’s exactly the case with Round Top. The proof comes with a careful look at its upper slopes. Most of Round Top is posted land, but there are several roads that circumnavigate the hill. On Heart’s Content Road, southwest of the hill, you can get a good look at Round Top. Up toward the top there is a great ledge of rock. It’s typical Catskill sandstone. Long ago, nearly 400 million years long ago, that sandstone made up the channel of an ancient river. The quartz sands of that river have hardened into rock. Quartz sandstone is among nature’s hardest and most durable rocks. Hence the cliff, but there’s more than that.

About 22 thousand years ago a very sizable glacier was advancing down the Hudson Valley. It filled the valley right up to the top of the Catskill Front. Indeed, it overflowed into the Catskills themselves. That, however, is another story. The important point here is that much of the time the ice overrode Round Top, the hill is only a little more than 1,400 feet tall and was not much of an obstacle to the flow of the ice. The glacier simply flowed across it.

Glaciers have a very predictable effect upon mountains that dare to get in their way. They tend to streamline the upstream side of the hill. That accounts for the smoothly rounded form of most of Round Top. The other thing that a glacier does is a little more difficult to explain. The downstream side of the impeding hill comes to be sculpted into a steep downstream-facing slope, often a cliff. The process is called “plucking.” The ice apparently adheres to the rock and yanks loose large chunks of it and drags it off. Over time a cliff results, a scar of the plucking process. That is the explanation for that sizable ledge at the top of the south side of Round Top.

Okay, so far, so good, it sounds like we have explained Round Top, but we haven’t. We understand the shape of Round Top but what is it doing there? Our curiosity is about why the mountain exists there at all. You see, the Hudson Valley glacier advanced down the valley at least from 25,000 to 14,000 years ago and that is a lot of time. It also passed down the Hudson Valley about 120,000 years ago during an event often called the Illinoisan glaciation. The passing ice plucked the Catskill Front as well as round Top and over time it sculpted the Wall of Manitou as the Catskill escarpment is sometimes called.

And that is our problem. How come Round Top didn’t get scoured away entirely during all of this glaciation? We don’t know and that bothers us.

We have been members of the Mountaintop Arboretum at Onteora Park in Tannersville pretty much since it was formed about 20 years ago. We have lost track of how many times we have made presentations there. But we are speaking at the Arboretum once again this Saturday, June 23, 2018 at 10:00 AM. We will be giving a PowerPoint presentation about the ice age and bedrock history of the Arboretum grounds. Then we will be taking our audience outside to do a geology walk across a good part of Arboretum property. It will be an easy walk across a relatively flat landscape. Try to come along, if you can fit it in to your schedule.

You may not be able to attend so we thought we would put together a bit of a quick guide for some time when you will be able to get out there. The main part of the Arboretum grounds are called the West Meadow and that is in the northwest corner of the property. Scattered across the West Meadow are the trees that make up the bulk of the Arboretum. You can visit and wander the trails that are there. You can look at the various species of trees which are all well labeled. There is even some art in the form of stone sculptures.

Map of West Meadow.

But, of course, when we are there, we see the geology, a lot of geology. We will be speaking about it all on Saturday, but let’s focus on the West Meadow today. To get there you travel north on Rte. 23C north from Tannersville until you reach the Arboretum. You can park on Maude Adams Lane and then walk back to the gate to the West Meadow. When we are there, we look across the grounds. What we see is a landscape that shows the effects of glaciation. We see what might be called an ice-scoured plain. That is, we see a glacier sweeping down from the North and overrunning the grounds of the Arboretum.

The most obvious manifestation of that is the exposed bedrock, right there at the gate. The bedrock, here, has been scoured by the passing ice. It has a smoothed and polished look to it. Wander around and look it over. You will, we think, be able to see the polish. Also, look for long straight scratches in the surface. They have a north to south compass orientation. These are glacial striations. If you have been a regular reader then you have seen these before. They were made as the glacier dragged cobbles and boulders across the surface. These are faint impressions and we couldn’t get a good photo, but you should be able to find them without much trouble.

Chattermarks

Next, watch for crescent shaped fractures in the rock surface. These are called chattermarks, they were formed when a boulder was dragged across this same surface. The weight of the ice pressed down, but the push of the glacier pushed it forward. When the push overcame the weight, the boulder “leaped” forward and “landed” leaving the crescent. Over time a series of crescents was formed.

Next, look around and you will soon see a large boulder. That’s something called a glacial erratic. That’s a boulder that was swept up and carried along by the advancing glacier. The boulder reached Arboretum grounds when the climate warmed and the glacier melted away. The boulder has been sitting here ever since the end of the Ice Age.

Glacial erratic

Now you know enough to be able to wander the grounds of the West Meadow. We are sure you will enjoy seeing all the trees that are there. After all, that is why the Arboretum was established. But now you will be able to understand and appreciate that this is an ice scoured plain. Watch for other ice scoured outcroppings; there is a very good on in the southeast corner of the meadow. You will see other glacial erratics as sell; they are scattered about all across Arboretum property. We hope you will just plain understand this landscape better.

This is a new installment of a series on the geology of Plattekill Clove, all written at the little red cabin owned by the Catskill Center for Conservation and Development. One of the great pleasures of staying at the cabin is walking, after full darkness, downhill to the bend in the road and gazing out onto the Hudson Valley. You can only see part of the valley from there, but it is a grand view. The most striking feature is the Kingston Bridge, all lit up and shining in the surrounding darkness. This is Thomas Edison’s breaking of four and one half billion years of nighttime black. Still, Nature had always had her own lightshows. The best part of the evening stroll is, on those occasional nights, when you can turn around and look west, and see the flashes of lightning from an approaching Catskills thunderstorm. If they are in season, the walk back is lit by the lightning bugs serenaded by crickets, and that can be positively intoxicating.

But daytime is when you are most active around the cabin. There are things that can only be seen then. The most rugged part of Plattekill Clove is found at its very top. That’s a complex stretch of canyons called the Devil’s Kitchen. It is a striking feature, easily viewed from the old stone bridge on the highway at the very top of the canyon. You crane your neck and look down what seems, and is, a precipitous drop.

A small stream descending down the mountain from the north has, over the eons, carved this . . . what to call it . . . not a canyon, not a ravine, perhaps just a jagged cut, no a jagged slash in the rock. The walls on both sides are shear vertical cliffs. They are so flat as to almost be shiny. None of this is accidental; the walls of rock that you are seeing are called joint planes.Hundreds of millions of years ago, great tectonic collisions had squeezed these rocks. Later, when the compression was ended and the rocks relaxed, they expanded and became brittle. That’s when they snapped and those perfectly flat and perfectly vertical fissures appeared. You need to pause and really look at them in order to truly appreciate their form, and their beauty.

After forming, so long ago, these joints sat in stillness for almost all of those hundreds of millions of years as the physical laws of inertia prevailed. Silent and unmoving they did absolutely nothing. But, that would change, especially with the coming of the Ice Age. That’s when they began to be affected by the harsh vicissitudes of glacial climates. Water seeped into these joints, it expanded, as it turned into ice in the freezing cold, and that resulted in further cracking. The expanding ice widened the fissures and they became broader and more prominent. That let still more water enter and chemical weathering followed. Nature was working on the old joints. She had become an artist, a sculptor in order to create something aesthetic from them.

But Nature is slow and patient; she is inexorable. The old fractures became active and they began to expand into the rock that lay between the joints. And those new fractures, in turn, expanded and widened themselves. Then they split and then the new fractures split again. Systems of fractures began to break up the rock. Still more water entered and still more ice formed and still more fracturing occurred.

Now the Ice Age ended. The climate warmed up but the winters would still be frigid and ice would perform its engineering at that time of the year, but something new would assist. Nature enlisted a new ally. That stream we spoke of earlier, made its appearance. Streams are also sculptors and good ones. This one descended the mountain and reached the Devil’s Kitchen. There it speeded up the sculpting process. During peak flows, the rivulet becomes a torrent and a powerful one. It can dislodge blocks of rock, sometime very large ones, and haul them off. Slowly, the Devil’s Kitchen took on its present form. One by one, great chunks of rock were knocked loose and carried away. Slowly that slash in the mountain became the steep, jagged and picturesque thing of natural beauty that it is today.

The old artists of the Hudson Valley School of art would have preferred the word sublime over picturesque and they would have had a point. The scene here is sublime in the sense that it portrays nature not as parkland, but as a rugged, certainly wild and even violent entity. We come here stand and we gaze at Devil’s Kitchen and we are overwhelmed by it; we should be. Contact the authors at randjtitus@prodigy.net.

Kaaterskill Falls has always been renowned for its scenic beauty. It first became widely known after the nearby Catskill Mountain House Hotel opened in 1824. From the hotel the young landscape artist, Thomas Cole, went exploring and visited the falls. He painted two of his most well-loved views here, one from the top of the falls and another from the bottom. You will have no trouble finding these images online. The falls have, subsequently, been painted by generations of artists who followed in Cole’s footsteps.

Generations of recreational hikers have also visited the falls and now the new staircase makes such visits much easier and far more practical. We have always admired the scenery at Kaaterskill Falls, but we are different from most others; when we visit the falls or look at those paintings, we see glaciers! We stand at the top of the falls and look down to see a glacier filling the valley below us; as we watch, it slowly rises up the canyon and then we have to step out of the way as it swells up over the falls themselves. We lift ourselves up into the air and turn around to watch as the flow of the ice continues on to South Lake. Geologists can do that sort of thing.

How can we claim such otherworldly visions, especially as scientists? It is an extraordinary claim and Carl Sagan said it best when he said “Extraordinary claims require extraordinary evidence.” Can we back up our “visions” with evidence? Yes, we can. It all began down at Bastion Falls where we began our trek several columns ago. We had climbed down from Rte. 23A and were about to ascend the canyon. But, we looked around and noticed a number of boulders with remarkable features on their surfaces. Take a look at our first photo; see one of these boulders. Notice that the surface of this rock is covered with large deep scratches. These are called glacial striations. This rock had been swept along with the flow of ice and dragged along for who knows how far. Along the way it was dragged up against many other similar rocks, and each impact left a scar in the form of a striation.

After seeing the first of these down at Bastion Falls, our eyes were trained to notice more – many more. These comprised the “extraordinary” evidence of the glacier that had, long ago, flowed down the Hudson Valley, risen up Kaaterskill Clove and then turned into the falls canyon. We kept finding more of those striated boulders as we climbed up all the way to the bottom of the falls. We realized that we had been following in the path of the glacier that had been here perhaps 14,000 years ago. But, the question remained: had that glacier ascended up and actually crossed over the top of the Kaaterskill Falls themselves. Those falls are 260 feet tall; could a glacier have actually “climbed” over them? We needed more extraordinary evidence. We climbed the new stairs and hiked on to the top of the falls hoping to find that evidence.

At the top of the new staircase a hiker is led to a dirt trail. That trail, in turn, leads to an intersection with the Blue Trail. A right turn there takes you on to the northern rim of Kaaterskill Clove; a left turn takes you to the top of the falls. We went left. Soon we were standing on the great ledge that makes up the top of the falls. We gazed down the canyon below and could not help but envision it filling with the ice of a glacier that slowly rose right up to where we were standing. But had that glacier actually passed this spot; had it risen and continued on to the north? We looked about and there was the evidence, something we had never noticed before at this spot.

It had been very dry in recent weeks and the flow of water was very low. Most of the bedrock at the bottom of the stream was now exposed and on its surface we found the evidence we had been looking for. The sandstone came from a Devonian stream channel and it contained several small quartz cobbles. These had been carried by that long-ago flow of water. All these cobbles had originally been rounded by the Devonian streamflow. But now, each one had had its upper half planed off. Its flat upper surface had been scraped flat so that it lay at exactly the same level as the surrounding sandstone (see our second photo). We were fortunate to have visited during a drought. Most of the time this ledge is very wet and very dangerous.

These were ice age features that we have frequently seen elsewhere at North Lake. When a glacier moves across a sandstone landscape it is likely to intersect cobbles within the country rock. It will plane right through them. These are fairly common on the Blue Trail at South Mountain and near Sunset Rock, but this was the first time we had seen them at the top of Kaaterskill Falls. They are features unique to the flow of glacial ice; we had our undisputable (and extraordinary) evidence. Our glacier had risen up over the falls and scoured off the tops of those pebbles as it continued upstream. But there was more.

At the top of Kaaterskill Falls lies a gigantic boulder (our third photo). Curiously, it does not have a name, but we immediately recognized it as being what is called a glacial erratic. Erratics are boulders that were swept up in the flow of ice and transported from where they came from and left where they are found today when the ice melted. This erratic had likely fallen off of South Mountain and onto and into our advancing glacier. It then flowed with the moving ice just to a site which would eventually be the top of the falls. Then the climate warmed, the ice melted and the erratic was lowered down to where it is seen today. It’s additional convincing evidence of the local glacier.

Climbing up to the top of this boulder is not easy but it is worth the effort. We did so and found the name Sanford Robinson Gifford inscribed on its top. Gifford was one of the most esteemed members of the Hudson River School of Art. He had painted here and commemorated his visit with the inscription. We wondered if he knew the ice age origins of this boulder.

One final treat for us was to walk down the dirt path that leads to the lands west of the falls. It only took us three minutes to get to the new deck with its knockout view of all of Kaaterskill Falls. We described that in the March 24th issue.

THE CATSKILLS rarely have a season of “dog days”, the time of hot, humid, heavy, stagnant air. That weather is the lot of more southerly climes. Up here, more often than not, our summers are nearly ideal: warm, dry and pleasant. However, that was not always the case. The rocks contain the record of a very different time in the history of our region, a very long time of perpetually unpleasant summer.

Drive along U.S. Route 20, in the vicinity north of Cherry Valley, and you will see some remarkable strata, the jet-black shales of a unit of rock called the Marcellus Group. All sedimentary rocks represent ancient environments, but it usually takes a while to decipher their

history. The Marcellus communicates its story as soon as it is seen. Its strata are thinly-bedded sedimentary rocks which were once the mud of an ancient ocean’s sea floor.

Robert last visited these rocks late in March with his stratigraphy class. At the time, a late winter snow flurry was approaching. In the cold cloudy sky, the Marcellus is an almost sinister looking sequence of rock: dark, forbidding and mysterious. And that’s exactly what it once was because the Marcellus records the history of the “poison sea” which once covered the western Catskill region.

Courtesy of the New York State Museum

It was the geography of the time that made the poison sea. The Catskill vicinity then lay in tropical latitudes so that the climate was quite warm, and so was the ocean. The ancient Acadian Mountains blocked the weather patterns which otherwise would have approached, riding through on the easterly trade winds. That’s the important part. You see, with the weather patterns blocked, there was relatively little wind blowing across the Catskill Sea and thus few currents to churn up that ocean. West of the Acadian Mountains, the sheltered sea became a hot, stagnant “soup”.

We can visit similar seas today. The Black Sea, though not on the equator, is a good example. Being land-locked, weather patterns do not much affect the Black Sea. The waters of such seas are usually stratified. Although the surface waters are very warm, they do contain a lot of oxygen and sea creatures can and do flourish in these shallow waters. It is different below; there bacteria consume all of the oxygen and the sea water becomes anaerobic, making it poisonous for any creatures who may wander in. They don’t; these waters are lifeless.

Such conditions persist right down to the bottom. As is normally the case with oceans, mud accumulates on the sea floor. The mud of oxygen‑poor seas is always jet black in color and, when it is compressed and hardened into rock, it becomes black shales. That’s how the Marcellus black shales formed.

Meanwhile, at the surface of the Catskill Sea, conditions were different. There was plenty of oxygen and a flourishing community of marine life. Masses of floating algae, with many small animals, thrived in a rich planktonic ecology, an oceanic jungle. Today we often call such a marine community a Sargasso.

Floating creatures seldom have skeletons and so they are rarely preserved as fossils. Consequently the Marcellus shales display only a few fossils for the careful hunter to find. Back in the 30’s Winifred Goldring, a paleontologist with the New York State Museum, studied the Marcellus and published some fine illustrations (figure three). Among her specimens, three (A, B and C) are tiny shellfish called brachiopods (brachs for short). Brachs will remind you of clams but they aren’t; they are an entirely separate group of shellfish. One specimen (D) is a clam. Notice that brachiopod shells have symmetry and the clam’s shell doesn’t. Pictures E and F are a puzzle. These creatures, called styliolinids, are extinct and we don’t know what they were. That’s a common problem with rocks this old. All of these invertebrates were small and lightweight. They could float in the surface waters of the poison sea, drifting as plankton or attached to floating wood or seaweed. Specimen G is different; it was an active swimmer. We call it a nautiloid and its descendants are still alive. The chambered nautilus, of the south Pacific, is today’s living nautiloid. Closely related to squids and octopods, the nautiloids had tentacles and well-developed eyes. They were active predators, swimming in the surface waters of the poison seas.

You can visit the shales of the poison sea yourself. From Cherry Valley, take county Rt. 166 northeast to Rt.20. Head west on 20 about half a mile and look for the shales on the north side of the road. You can see a better exposure if you head east on Rt. 20 and travel 2.6 miles, where you will reach Chestnut Street. There you will find an outcrop with two units of shale separated by about five feet of gray limestone.

If you patiently pick through the shales, you will certainly find many styliolinids; watch carefully as they are very small. With luck you may find some of the other fossils as well. I have seen some very fine fossil snails below the limestone at the eastern outcrop. That limestone can also be a lot of fun too. This unit represented a temporary break from the poison sea conditions. For a period of time a shallow, oxygenated, tropical sea prevailed here. The limestone has a number of fossils in it, typical of such seas.

The poison seas are misnamed; there were never any active toxins in them, just an absence of oxygen. Nature does that from time to time. The lesson we learn from the poison seas is not that nature creates inhospitable environments, but that she allows life enough time to adapt to her conditions. The planktonic creatures of the Marcellus black shales thrived just a few feet above one of nature’s most inhospitable environments.

* * *

Visiting the Marcellus shales is not the same as seeing the poison sea itself. To do that, pick one of those hot, humid but clear summer days and, in the stillness of the early evening, find a vantage point looking down upon the valley of the Mohawk. The Chestnut Street site may do. From here you can still see the entire expanse of the old poison sea, stretching from the eastern to the western horizons. You are a little above the old sea level, and the atmosphere is just as it was back then.

The summer sun is setting in the northwest and, as it approaches the horizon, the valley of the Mohawk darkens and flattens into a land of somber colors. The fields become a brownish, algae green; the forests turn jet black. To the northwest, the horizon becomes the image of a very still sea. Back to the east there is a distant bank of clouds. As this eastern horizon darkens, those clouds sharpen into the clear vision of the peaks of the ancient Acadian Mountains. Distant mountain ranges often masquerade as clouds, and there is always a shock of surprise when one recognizes the illusion. The lower Acadian slopes are a dark blue brown; they are already in the shade. The jagged pinnacles are small brilliant pyramids; they still reflect the sun.

The air is absolutely still and the surface of the poison sea is as flat as water can be. Gauzy clouds of green algae alternate with bottomless pools of black waters. Occasionally, bubbles of fetid gas rise to the surface and oily dots mar the blackness. Only these betray the suffocating gloom in the depths below. Small, delicate wakes encircle the green; unseen predators are hunting unseen prey. Now a few swells pass heading westward, waves reflected off the distant coast. The green patches lazily drift back and forth in these oceanic breezes. Abruptly there is a disturbance, a quick splash and, for a split second, a mass of tentacles, a single eye and then a brown and white striped shell are seen breaking the water.

Quiet quickly returns as the sun sets and the sea darkens. The evening stars now appear and they seem to be reflected on the glassy sea below. But these reflections gradually blur, and they enlarge into luminous patches of light. Phosphorescent plankton are completing their evening ascent. Their dim glow is all that will light the dark of this Paleozoic sea.

In the growing dark, the image of the poison sea dims. The bioluminescent patches shrink and sharpen into yellow pinpoints of light. Far below, the electric lights of the Mohawk Valley are coming on and now it is they which reflect the stars above. The poison sea is gone, long gone, just an image in the eye and mind of the pensive geologist.

The Shawangunk Mountains are certainly among the most scenic locations in our region, and uniquely so. This ridge of resilient quartz sandstone towers above the Hudson Valley. One of its most popular locations is Sam’s Point Preserve, near the south end of the mountains. It’s thousands of acres are perched atop the mountains at elevations well above 2,000 feet. It’s owned by the Open Space Institute and managed by the Nature Conservancy. In the past there were commercial uses of this land. There were abundant blueberries here, and people were hired, every summer, to come and pick them. Then, in addition, there have been several resort hotels.

But we came here to learn about the geology. How had the area’s geological history given rise to this scenic wonder? We headed up the trail. It didn’t take long to figure out why the Shawangunks are even there. All along the trail were massive outcrops of quartz sandstone and conglomerate. Quartz is very resistant to weathering and a mountain made out of such rocks will stand out as all other bedrock around it erodes away.

We got up to Sam’s Point itself and soon learned much more about the geological history that went into creating the landscapes we see today. We arrived at the easternmost of two sandstone platforms, each seemingly designed for sight-seeing. Naturally, we were more interested in looking down at the rocks than gazing at the distant scenic views. There was some special things that caught our eyes.

We saw a polished sheen and faint scratches on the surface of the rock. We quickly recognized these to be common ice age features. Sam’s Point has had a long ice age history, probably going back to the time when glaciers first came down the Hudson Valley. At that time this site had ice passing across it. The ice was dirty, carrying a great deal of sand along with it, mostly concentrated at its base. The sand, probably mixed with a lot of silt and clay, actually polished the bedrock. It sanded it down and planed it off.

There was more. The glaciers carried with them a large number of cobbles and boulders. As these were dragged across the surface, they gouged scratches into the bedrock. Geologists call these glacial striations. We have seen such surfaces many times so it was hardly a great revelation, but it did speak clearly to us of the fact that there had once been a sizable glacier here. Then we saw more.

We looked up and there was Sam’s Point itself. It is another natural platform of quartz sandstone, but this one is bounded by a vertical cliff, a big one. Most people would enjoy it as a fine scenic overlook, but our eyes took us back into the Ice Age. Geologists call features like Sam’s Point scour and pluck topographies. These are common and each is the product of the passage of the ice. The Hudson Valley glacier advanced from the north and, as it crossed Sam’s Point, it scoured and striated that platform at the top of the cliff. That’s the scour part. Then, as the ice continued south, it stuck to the bedrock and then yanked enormous masses of it loose and carried them off. That left gaping scars in the mountaintop and one of them is the cliff of Sam’s Point. That is also the pluck part of this landscape. The cliff faces a compass direction of south-30 degrees-west. That, presumably, was the direction the glacier was traveling. We looked at the striations beneath us, and we had a compass. They had the same orientations.

Now we had a nice, coherent explanation for the topography of Sam’s Point. That’s what scientists call an elegant solution to a scientific problem. We would have been flushed with pride at having made such marvelous discoveries, were it not for the fact that thousands of other geologists had preceded us here, and they had, no doubt, all come to the very same conclusions.